Conventionally, in a mass spectrometry system in which a plurality of quadrupole electrode systems each of which includes at least four rod-like electrodes and in each of which a DC voltage U and a radio frequency (RF) voltage VRF cos (Ωt+Φ0) are applied to the rod-like electrodes are connected in tandem, one of the plurality of quadrupole electrode systems is filled with a buffer gas and functions as a collision chamber that dissociates (collision induced dissociation) target ions with collision against the buffer gas. In particular, passing speed of ions passing through the quadrupole electrode system in the collision chamber is reduced by collision against the buffer gas, and therefore there is a high possibility that delay of the ions passing through the collision chamber has a bad influence such as crosstalk on a mass spectrum serving as a result of mass spectrometry. Thus, in order to accelerate decelerated ions, there is employed means for generating a potential gradient of a DC component in a direction of travel of the ions.
As illustrated in FIG. 5, in Patent Literature 1, as means for accelerating ions in a collision chamber, four rod-like electrodes (4-2-a, 4-2-b, 4-2-c, and 4-2-d) whose diameters are gradually changed are alternately disposed in opposite directions, and an RF voltage −V cos Ωt and a micro DC voltage ΔUy are superimposed and applied to the facing electrodes (4-2-a and 4-2-c) and an RF voltage +V cos Ωt and a micro DC voltage ΔUx are superimposed and applied to the other facing electrodes (4-2-b and 4-2-d). With this, a potential gradient of a DC component is generated on a central axis of the electrode system. A numerical analysis result of a potential of the DC component generated on the central axis at this time is illustrated in FIG. 6. It is found that the potential of the DC component is inclined in a direction of travel of ions (z direction). With this, ions passing through the inside are accelerated.